1. Field of the Invention
The present invention relates to a display system for a vehicle to be mounted on the vehicle, and a virtual image projected on a projection area of the vehicle, onto which area light outgoing from the backlight passed through the indicator is projected, and a front view of the vehicle to be seen from an eye point of the vehicle through the projection area are seen in a superimposed manner.
2. Description of the Related Art
Recently, with increase and diversification of information required by a driver during a drive, a projection-type display unit called a head-up display (HUD) device has been adopted so that information, which cannot be displayed in a meter unit due to the lack of the space, is displayed on a windshield as a virtual image, thereby a driver can see the foreground of the vehicle through the windshield together with the virtual image, which is superposed upon the foreground. As shown in a patent document 1, in the HUD device, it is known to use a liquid crystal display (LCD) or a natural light device of a vacuum fluorescent display (VFD) as an indicator (display device), which displays a virtual image on a windshield.
A backlight of an indicator which is used in a HUD device has two major types, an edge-light type and a direct-light type. In the edge-light type, a ray from illuminant (CCT, LED, etc.) arranged on an end part of a light guide plate is transmitted on a specific area by using the light guide plate and is reflected. That is, a backlight of the edge-light type is a surface illuminant. The edge-light type can give uniform surface brightness through a diffuser plate which is arranged between the surface light source and the indicator. In the direct-light type, a light source of LED is arranged behind an indicator, and light which is diffused by a diffuser plate is transmitted. Thereby, the direct-light type has high brightness compared to the edge-light type.
Patent Document 1:                Japan published patent application 2002-293162        